Re: [PATCH] workqueue: Create kworker only for boot CPU pool prior SMP initialization
From: Tejun Heo
Date: Mon Apr 04 2022 - 18:01:15 EST
On Thu, Mar 31, 2022 at 09:14:35PM +0800, Zqiang wrote:
> The workqueue_init() is called before SMP initialization, which
> means only the boot CPU is online, just create kworker for boot
> CPU pool.
>
> Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx>
> ---
> kernel/workqueue.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index abcc9a2ac319..3948babe02d5 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -6120,11 +6120,9 @@ void __init workqueue_init(void)
> mutex_unlock(&wq_pool_mutex);
>
> /* create the initial workers */
> - for_each_online_cpu(cpu) {
> - for_each_cpu_worker_pool(pool, cpu) {
> - pool->flags &= ~POOL_DISASSOCIATED;
> - BUG_ON(!create_worker(pool));
> - }
> + for_each_cpu_worker_pool(pool, smp_processor_id()) {
> + pool->flags &= ~POOL_DISASSOCIATED;
> + BUG_ON(!create_worker(pool));
I mean, I guess this would work but what's the benefit? It doesn't make any
practical difference and the code is now more fragile to external changes.
Thanks.
--
tejun